foo.c: In function 'ss':
foo.c:17:12: warning: unused variable 'x1' [-Wunused-variable]
  int sum=0,x1,xt;
            ^~
foo.c: In function 'main':
foo.c:7:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ^~~~~~~~~~~~~~
foo.c: In function 'ss':
foo.c:18:4: warning: 'xt' is used uninitialized in this function [-Wuninitialized]
  xt=xt/10;
  ~~^~~~~~

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